Ammonia is a compound of hydrogen and nitrogen with the formula of NH3. It is a gas with a characteristic pungent smell at room temperature. Ammonia is included at a small amount in the atmosphere, at a trace amount in natural water, and may be produced when bacteria decompose a nitrogen organic matter in the soil.
Ammonia is used as a raw material in various chemical industries, as a raw material for preparing ammonia water, and as a solvent for preparing an ionic material. The most common method for producing ammonia from hydrogen and nitrogen is the Haber-Bosch process, and the process involves an exothermic process that releases 100 kJ of energy as a result of producing two molecules of ammonia by binding one nitrogen molecule and three hydrogen molecules as shown in Formula 1 in the presence of an iron or ruthenium catalyst. However, although this is a large scale industrial process, a yield of ammonia needs to be reduced to 10% to 20%, and the process requires additional energy and hydrogen.N2+3H2→2NH3+100 kJ  [Formula 1]
Alternatively, an electrochemical ammonia synthesis method using an ion conductive oxide electrolyte has been suggested. Also, in the method, steam may be used as a source of hydrogen, and the steam may be converted to protons on a surface of the ion conductive oxide and reacted with nitrogen at a low pressure (atmospheric pressure).
U.S. Pat. No. 7,811,442 is related to an ammonia synthesis apparatus for synthesizing ammonia by using a proton conductive solid oxide of a tube type as an electrolyte and supplying an external current.
European Patent No. 0 972 855 is related to an ammonia synthesis apparatus for synthesizing ammonia by using a proton conducting solid oxide of a flat type and supplying an external current.